Convertible Debt (Details) (USD $)					3 Months Ended		9 Months Ended				1 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2013 2013 Convertible Senior Notes [Member]	Sep. 30, 2014 2015 Convertible Senior Notes [Member]	Sep. 30, 2014 Convertible Senior Notes [Member]	Sep. 30, 2013 Convertible Senior Notes [Member]	Sep. 30, 2014 Convertible Senior Notes [Member]	Sep. 30, 2013 Convertible Senior Notes [Member]	Sep. 30, 2013 Convertible Senior Notes [Member] 2013 Convertible Senior Notes [Member]	Feb. 15, 2013 Convertible Senior Notes [Member] 2013 Convertible Senior Notes [Member]	Jun. 29, 2012 Convertible Senior Notes [Member] 2015 Convertible Senior Notes [Member]	Sep. 30, 2014 Convertible Senior Notes [Member] 2015 Convertible Senior Notes [Member]	Sep. 30, 2013 Convertible Senior Notes [Member] 2015 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage										2.75%		4.50%
Convertible Notes Payable, Current	$ 18,000,000	$ 0		$ 18,000,000
Convertible senior notes	0	18,000,000	18,000,000
Debt Instrument, Convertible, Conversion Ratio											117.2333
Debt Instrument, Convertible, Conversion Ratio, Principal Amount											1,000
Debt Instrument, Convertible, Conversion Price											$ 8.53
Debt Instrument, Call Feature, Call Price, Percent of Principal											100.00%
Debt Instrument, Interest Rate, Effective Percentage									3.73%			4.50%	4.50%
Contractually stated interest costs					203,000	203,000	608,000	666,000
Amortization of interest costs					11,000	11,000	32,000	50,000
Short-term Debt, Fair Value	$ 17,900,000	$ 17,800,000